Distribution of perfluorooctanoic acid in exposed female post-pubertal pigs in thermal neutral or heat stressed conditions.

Perfluorooctanoic acid (PFOA), a legacy perfluoroalkyl substance with immuno- and repro-toxicant effects, has poorly characterized bioaccumulation and distribution patterns in female pigs. The potential for heat stress to influence PFOA partitioning, potentially through intestinal hyperpermeability and alterations in systemic blood flow, also warrants investigation. This study investigated PFOA uptake, accumulation, and distribution in thermal neutral and heat-stressed gilts. Pigs (n = 48) were estrus synchronized and experienced thermal neutral (TN; 20 °C) or heat stress (HS; 26.6 to 32.2 °C) conditions during which they consumed 70 ng/kg bodyweight PFOA via cookie dough as vehicle control daily. Plasma was collected on d 1, 15, and 20. Liver, ovary, and follicular fluid were collected at euthanasia (d 20). Post-exposure, PFOA was detected in serum, liver, ovary, and follicular fluid. Heat stress increased (P < 0.05) plasma PFOA compared to TN pigs on d 15, but on d 20, plasma PFOA levels in TN and HS pigs were similar. Liver PFOA concentrations were similar between TN and HS pigs. Ovarian PFOA levels tended (P = 0.06) to be higher in TN relative to HS pigs, with an opposing pattern in follicular fluid, in which PFOA concentrations were greater (P < 0.05) in HS pigs. These findings suggest that PFOA apportions to plasma, liver, ovary, and follicular fluid of exposed pigs and that heat stress alters PFOA distribution, which could negatively impact reproductive health. This study underscores the need to consider the interaction of heat stress and toxicant exposure in environmental health risk assessments.